# NOT RUN {
# The data frame EPA.97.cadmium.111.df contains calibration data for
# cadmium at mass 111 (ng/L) that appeared in Gibbons et al. (1997b)
# and were provided to them by the U.S. EPA.
# Display a plot of these data along with the fitted calibration line
# and 99% non-simultaneous prediction limits. See
# Millard and Neerchal (2001, pp.566-569) for more details on this
# example.
Cadmium <- EPA.97.cadmium.111.df$Cadmium
Spike <- EPA.97.cadmium.111.df$Spike
calibrate.list <- calibrate(Cadmium ~ Spike, data = EPA.97.cadmium.111.df)
newdata <- data.frame(Spike = seq(min(Spike), max(Spike), len = 100))
pred.list <- predict(calibrate.list, newdata = newdata, se.fit = TRUE)
pointwise.list <- pointwise(pred.list, coverage = 0.99, individual = TRUE)
dev.new()
plot(Spike, Cadmium, ylim = c(min(pointwise.list$lower),
max(pointwise.list$upper)), xlab = "True Concentration (ng/L)",
ylab = "Observed Concentration (ng/L)")
abline(calibrate.list, lwd = 2)
lines(newdata$Spike, pointwise.list$lower, lty = 8, lwd = 2)
lines(newdata$Spike, pointwise.list$upper, lty = 8, lwd = 2)
title(paste("Calibration Line and 99% Prediction Limits",
"for US EPA Cadmium 111 Data", sep = "\n"))
#----------
# Clean up
#---------
rm(Cadmium, Spike, newdata, calibrate.list, pred.list, pointwise.list)
graphics.off()
# }
Run the code above in your browser using DataLab